This application contains a Microfiche Appendix comprising a single Microfiche with 14 frames containing the material described in Appendices A-G of the specification.
1. Field of the Invention
The invention is directed to a data acquisition system and, more particularly, to a seismic data acquisition system.
2. Description of Related Art
Systems for conducting seismic exploration are well known in the art. On land, a plurality of transducers are deployed over a region and configured to receive reflections of acoustic signals from different geophysical layers beneath the surface of the earth. Seismic sensors are connected over cables to signal conditioning, digitization and digital recording equipment. When utilizing a seismic system, a strong acoustic signal is generated by, for example, setting off an explosion or by utilizing an acoustic signal generator having a relatively high power output. Reflections of the acoustic signals from the geophysical layers are then received at the seismic sensors deployed over a given area and the signals recorded, typically, for later analysis.
One problem with seismic exploration is that it frequently occurs in remote areas. Once sensors are deployed over a large area and seismic data gathered, great expense would be incurred if data were corrupted by malfunctioning sensors or electronics and a seismic survey crew needed to return again to the site, set up equipment and re-gather the data.
Seismic exploration has exacting requirements for seismic sensors and for the electronics which processes the signals derived from seismic sensors. There is therefore a need to be able to test both the sensors and related equipment to ensure that both the devices and the associated electronics are functioning properly. It is important that the seismic data gathering equipment be able to synchronize the data gathered with the explosion used for a measurement. This is somewhat difficult when the timing of the explosion with respect to the triggering signal is unpredictable, as it is with, for example, dynamite.
The invention is directed to a data acquisition system having a central station and a plurality of nodes. Each node is connected to receive signals from one or more sensors ad each is configured to have substantially the same transmission delay to said central station. The central station is configured to notify all nodes of an event time at which a data event, such as a seismic shot, occurred.